Department of Bioscience, Aarhus University, DK-8000 Aarhus C, Denmark.
Department of Bioscience, Aarhus University, DK-8000 Aarhus C, Denmark.
J Insect Physiol. 2019 Oct;118:103940. doi: 10.1016/j.jinsphys.2019.103940. Epub 2019 Sep 4.
Insects are known to selectively balance their intake of protein and carbohydrate to optimize reproduction and survival. For insects who feed on decomposing fruit, fluctuations in macronutrient composition occur as fruits ripe and decomposition progresses which may challenge optimal resource allocation. Using Drosophila melanogaster, we tested the effect of macronutrient fluctuations and the variability of these fluctuations on starvation resistance and components of reproductive output; traits known to be sensitive to different protein to carbohydrate (P:C) ratios in the diet. For 8 days, flies were fed the same protein to carbohydrate (P:C) ratio (constant feeding), or fed diets with fluctuations in P:C ratio on each day; these fluctuations being regular (predictably fluctuating) or irregular (unpredictably fluctuating). The three feeding regimes yielded the same average P:C ratio across the duration of the experiment. We found no difference in starvation resistance across the feeding regimes. Interestingly, there was a sexual dimorphism in the effect on reproductive output with males performing worst in the unpredictable feeding regime, and with no effect of feeding regime on female performance. Our study provides evidence for means of adapting to fluctuating macronutrient composition and suggests females are more tactful than males in storing and allocating resources for reproduction.
昆虫已知会选择性地平衡蛋白质和碳水化合物的摄入量，以优化繁殖和生存。对于以腐烂水果为食的昆虫来说，随着水果成熟和分解的进行，宏量营养素组成的波动可能会挑战最佳资源分配。我们使用黑腹果蝇（Drosophila melanogaster）测试了宏量营养素波动及其波动的可变性对饥饿抵抗和生殖输出成分的影响；这些特征已知对饮食中不同的蛋白质与碳水化合物（P:C）比例敏感。在 8 天的时间里，果蝇被喂食相同的蛋白质与碳水化合物（P:C）比例（恒定喂食），或每天喂食 P:C 比例波动的饮食；这些波动是规则的（可预测的波动）或不规则的（不可预测的波动）。在实验的整个过程中，三种喂养方式的平均 P:C 比例相同。我们没有发现饥饿抵抗在喂养方式上有差异。有趣的是，在生殖输出方面的影响存在性别二态性，雄性在不可预测的喂养方式下表现最差，而喂养方式对雌性表现没有影响。我们的研究为适应波动的宏量营养素组成提供了证据，并表明雌性在储存和分配资源用于繁殖方面比雄性更机智。
